The present invention relates to dynamic splints or braces for applying torque across joints undergoing rehabilitative therapy.
Injuries or surgery to wrists, elbows, knees and other joints often result in flexion or extension contractures. These debilitating conditions prevent the patient from fully flexing (in the case of an extension contracture) or extending (in the case of a flexion contracture) the injured joint. Range-of-motion or ROM splints are dynamic devices commonly used during physical rehabilitative therapy to increase the range of motion over which the patient can flex or extend the joint. Splints of this type are generally known, and disclosed, for example, in the Mitchell et al. U.S. Pat. No. 5,036,837.
Commercially available range-of-motion splints typically include spring loaded brace sections for applying torque to the injured joint in opposition to the contracture. This force tends to gradually increase the working range or angle of joint motion. Springs, however, are passive devices and exert decreasing amounts of force as they retract. The amount of decrease in torque per change in the angle of the brace sections is known as the apparent elasticity of the splint. Most range-of-motion splints, therefore, require continual adjustment to maintain a constant amount of applied torque as the patient's range of joint motion increases during therapy. These torque adjusting procedures are time consuming and inconvenient.
It is evident that there is a continuing need for improved range-of-motion splints. In particular, there is a need for splints capable of applying relatively constant torque over the entire working joint angle range without adjustments. The amount of torque applied by the splint should also be adjustable to suit the needs of different patients. To be commercially viable, any such splint must be convenient to use and operate, and capable of being efficiently manufactured.